This invention relates to magnetic tags, and more specifically to ammunition cartridges in which magnetic tags are exposed for purposes of identification.
Present day cartridge cartridge ammunition for rifles and pistols, particularly for civilian use, is of two basic types: center-fire and rimfire. Both types typically possess a projectile portion which is streamlined for aerodynamic reasons and typically comprises a soft metal such as lead, a lead based alloy or cladded lead composite. The projectile portion is fitted into a casing portion which is typically brass. An explosive material, such as smokeless gunpower, is disposed within the casing and sealed therein by the projectile portion of the cartridge. Additionally, in center-fire ammunition there is disposed a primer located at the end of the casing opposite the open end into which the projectile is fitted. The primer comprises a primer case and a primer esplosive which is typically detonated by the impact of a firing pin on the primer case. Thus, in center-fire ammunition cartridges, the detonation of the primer acts to detonate the main explosive powder charge which accelerates the projectile along the barrel of the rifle or pistol into which the cartridge has been inserted. Rimfire ammunition cartridges work in the same way except that the primer explosive is not centrally located and typically is not disposed in its own casing.
In its passage through the barrel of the weapon employed, the projectile is usually impressed with markings (rifling) which can be used to match the projectile, when recovered, with the weapon from which it was fired. Police and other investigative agencies have long used this method of identification to match a projectile with the owner or user of the weapon from which it was fired. Other than this, there is no other significant means of identification in use.
It is highly desirable to have a method for more directly associating the projectile, the casing, or the entire cartridge with an individual user or purchaser. At present, a cartridge or the casing may be traceable to a given manufacturer, assuming he has placed his name or trademark thereon. However, it is not now possible to identify the projectile or casing by lot number, point of sale, distributor, shift of manufacture, type of main explosive charge, type of primer, amount of explosive charge, or other relevant identifying characteristic. Such information is very valuable to ballistics experts and crime prevention agencies.